1. Field of the Invention
This invention relates, in general, to a system useful in the silk-screen printing of relatively small, flat objects such as compact discs and floppy disks for computers. More particularly, it relates to a silk-screen printing system comprising in combination apparatus means for the automatic transport of compact discs in stepwise fashion, one-at-a-time, in a horizontally disposed circular-defined path, and the silk-screen printing of such compact discs, means for automatic loading of compact discs onto the transport apparatus one-at-a-time from a vertically disposed stack of a plurality of such discs superposed one above the other in horizontal fashion and for off-loading printed discs from the transport apparatus one disc at-a-time, and providing them in a vertically disposed stack of a plurality of horizontally disposed printed discs superposed one above the other, and apparatus means for supplying and receiving such compact discs in a plurality of vertically disposed stacks. Even more particularly, the invention relates to the specific transport means, load/off-loading means and supplying/receiving means used in the system combination.
2. Description of the Prior Art
Heretofore, others have invented apparatus for the silk-screen printing of compact discs with three colors. One such apparatus of which applicants are aware, and which has been used now for sometime, comprises, in general, a horizontally disposed, annular-shaped, rotatable member onto which compact discs are loaded one-at-a-time in a certain predetermined timed sequence and transported from a loading to an unloading station through the various work stations. As the transport member rotates, the discs are transported from the loading station to the various printing stations, at which stations the top planar surfaces of the horizontally disposed compact discs are each printed one-at-a-time with the color of the desired information. Following printing, the rotatable member transports the printed discs to a curing station whereat the printing ink is cured in conventional fashion by, e.g., an ultraviolet (UV) curing means. Subsequently, the discs are unloaded from the rotatable member for further handling, as desired.
Although this known compact disc printing system does the job for which it is intended, i.e., prints compact discs with 3-colors each having the desired information, its use is accompanied, nevertheless, with certain problems or disadvantages. Of critical concern is the location of the silk-screen printing apparatus relative to the annular-shaped rotatable transport member.
The silk-screen printing apparatus in this known device is supported on support means located outside the outer perimeter of the annular-shaped, rotable transport member. During printing of each of the compact discs, the silk-screen squeegee and flood bar moves radially inwardly across the disc and rotatable transport member and then radially outwardly, retracting to its initial rest position outside the outer perimeter. The transport member, in this known apparatus, is fixedly secured at its inner periphery, to a circular-shaped support member. Thus, as the support member is rotated, the transport member rotates. In essence, the annular-shaped transport member and circular-shaped support member constitute one rather large diameter rotatable member having only a relatively small diameter center opening. As a result, the space occupied by the circular-shaped support member is not only underutilized, but wasted as well. Moreover, as the silk-screen printing apparatus in this known device is located outside the perimeter of the rotatable compact disc transport member, the printing system occupies and takes up considerable floor space that may not be readily available for such an installation or is otherwise needed. Perhaps, more importantly, however, the location of the printing apparatus in the system now being used presents considerable difficulty to the operator in set-up and change-over of the printing apparatus for the printing of various different compact discs. This is due to the fact that the silk-screen printing apparatus is so located relative to the annular-shaped transport member that it faces inwardly toward the center of the apparatus. Thus, the operator, necessarily must bend over the rotatable transport member in a somewhat contorted manner to accomplish change over or other tasks associated with the printing apparatus.
Furthermore, in this known compact disc printing system, the compact discs, in general, are loaded and off-loaded onto and from the transport member by means that are relatively complex involving numerous interworking components in combination. This apparatus, like the transport means, occupies considerable floor area that needs to be better utilized.
Subsequent to loading, the compact discs are each more precisely registered on the transport member prior to being transported to the first of the three printing stations. This is accomplished, in general, by a centering pin apparatus located vertically above the transport member. Thus, in general, the centering pin is caused to intrude into the center opening of the compact disc from the top surface thereof causing the compact disc to move somewhat, even though a relatively small distance, across and in contact with the surface of the disc fixture located on the transport member. This is highly undesirable, however, as the surface in contact with the fixture is the bottom surface of the disc on which the recording is provided. This results in occasional marring of the disc recording surface, leading to a disc that may be entirely unsuitable for sale.
Thus, there is need for a printing system for compact discs that not only automates the entire process, but, also, takes up less floor space. Further, there is need for such a printing system wherein the relative locations of the disc transport apparatus and printing apparatus are such as to also facilitate set up and change over or other tasks that need be accomplished on the silk-screen printing apparatus. And, there is needed a means for centering of a compact disc on the transport member prior to printing the disc that results in no, or at least less, marring or otherwise adversely affecting the disc.